Lithium ion battery and electrolyte thereof

Abstract

The invention provides a lithium ion battery and electrolyte thereof. The electrolyte of the lithium ion battery comprises a non-aqueous organic solvent, a lithium salt dissolved in the non-aqueous organic solvent, and an additive dissolved in the non-aqueous organic solvent, wherein the additive comprises FEC (fluoroethylene carbonate) which accounts for 1-15 mass percent of the electrolyte, 1,3-propane sultone (PS) which accounts for 0.5-10 mass percent of the electrolyte, and oxalate which has a structure in a formula I (which is as shown in the description) and contains two double bonds; the oxalate accounts for 0.01-5 mass percent of the electrolyte; n in the formula I is selected from integer of 0-4. The lithium ion battery comprises a positive pole piece, a negative pole piece, an isolating membrane isolated between the positive pole piece and the negative pole piece adjacent to each other, and the electrolyte. The lithium ion battery has excellent charging and discharging cycle performance under high temperature and high voltage. (img file= 'DDA0000455073110000011.TIF' wi= '1320' he= '208' /).

Description

technical field [0001] The invention relates to the field of batteries, in particular to a lithium ion battery and its electrolyte. Background technique [0002] With the popularity of electronic mobile devices such as notebook computers, mobile phones, handheld game consoles, and tablet computers, people have higher and higher performance requirements for electronic mobile devices. However, the higher the performance and the more fancy the function of electronic products, the faster the power consumption, so people urgently need lithium-ion batteries with higher energy density. [0003] When increasing the energy density of the lithium-ion battery (such as increasing the voltage of the lithium-ion battery), it is equivalent to increasing the activity of the electrochemical reaction of the electrolyte. At this time, the electrolyte will undergo a violent redox reaction on the positive and negative electrodes, but at the same time Along with a large number of side reactions,...

AI Technical Summary

Problems solved by technology

In lithium-ion batteries, additives 1,3-propane sultone (PS) and fluoroethylene carbonate (FEC) are often used to improve cycle performance. The Chinese patent application publication number CN102005606A discloses a certain amount of PS The electrolyte with FEC can form a film on the surface of the negative electrode to improve the cycle performance of lithium-ion batteries, but when the voltage is increased to 4.4V, this combination cannot meet the requirements for improving the cycle performance of lithium-ion batteries

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